"A man has always to be busy with his thoughts if anything is to be accomplished"

In this quote, Antonie van Leeuwenhoek highlights the importance of being psychologically engaged in order to attain success. He suggests that a person must constantly be occupied with their thoughts in order to achieve anything significant. This indicates that simply going through the movements or being physically hectic is insufficient; one need to likewise be actively believing and planning in order to make development. Van Leeuwenhoek's words serve as a pointer that true accomplishment requires both physical and mental effort. It is a call to be deliberate and purposeful in our actions, and to never underestimate the power of our ideas in attaining our goals.